Kelly Clarkson vs. Carrie Underwood: Who would YOU say is the most successful 'American Idol' alum?

Image Credit: Sylvain Gaboury/PR Photos; Albert L. Ortega/PR PhotosIf I attempted the Herculean task of debating the reasons one former Idol is more successful than another within the space of this post, you’d be up for reading of Doc Jensen proportions. So when Billboard ranked the former Idol contestants based on the musical achievements, they only factored in cold, hard numbers (album and single sales, plus radio play). The winner? The original: Kelly Clarkson.

Everyone has their favorite Idol grads (I love me some Cookie), but no matter who your personal No. 1 is, it’s undeniable that the two most musically prominent spawns of Idol are Kelly and Carrie. But success is so much more than numbers. That in mind, which of these two vocal powerhouses do you think comes out on top, PopWatchers? Vote below!